/*
 *  RFC 1521 base64 encoding/decoding
 *
 *  Based on TropicSSL: Copyright (C) 2017 Shanghai Real-Thread Technology Co., Ltd
 *
 *  Based on XySSL: Copyright (C) 2006-2008  Christophe Devine
 *
 *  Copyright (C) 2009  Paul Bakker <polarssl_maintainer at polarssl dot org>
 *
 *  All rights reserved.
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions
 *  are met:
 *
 *    * Redistributions of source code must retain the above copyright
 *      notice, this list of conditions and the following disclaimer.
 *    * Redistributions in binary form must reproduce the above copyright
 *      notice, this list of conditions and the following disclaimer in the
 *      documentation and/or other materials provided with the distribution.
 *    * Neither the names of PolarSSL or XySSL nor the names of its contributors
 *      may be used to endorse or promote products derived from this software
 *      without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 *  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 *  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 *  FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 *  OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 *  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
 *  TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 *  PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#if 1 // defined(TINY_CRYPT_BASE64)

#include "tiny_base64.h"
#include "uc_log.h"
#include "rtthread.h"

static const unsigned char base64_enc_map[64] = {
    'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J',
    'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T',
    'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd',
    'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
    'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x',
    'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7',
    '8', '9', '+', '/'};

static const unsigned char base64_dec_map[128] = {
    127, 127, 127, 127, 127, 127, 127, 127, 127, 127,
    127, 127, 127, 127, 127, 127, 127, 127, 127, 127,
    127, 127, 127, 127, 127, 127, 127, 127, 127, 127,
    127, 127, 127, 127, 127, 127, 127, 127, 127, 127,
    127, 127, 127, 62, 127, 127, 127, 63, 52, 53,
    54, 55, 56, 57, 58, 59, 60, 61, 127, 127,
    127, 64, 127, 127, 127, 0, 1, 2, 3, 4,
    5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
    15, 16, 17, 18, 19, 20, 21, 22, 23, 24,
    25, 127, 127, 127, 127, 127, 127, 26, 27, 28,
    29, 30, 31, 32, 33, 34, 35, 36, 37, 38,
    39, 40, 41, 42, 43, 44, 45, 46, 47, 48,
    49, 50, 51, 127, 127, 127, 127, 127};

/*
 * Encode a buffer into base64 format
 */
int tiny_base64_encode(unsigned char *dst, int *dlen, unsigned char *src, int slen)
{
    int i, n;
    int C1, C2, C3;
    unsigned char *p;

    if (slen == 0)
        return (0);

    n = (slen << 3) / 6;

    switch ((slen << 3) - (n * 6))
    {
    case 2:
        n += 3;
        break;
    case 4:
        n += 2;
        break;
    default:
        break;
    }

    if (*dlen < n + 1)
    {
        *dlen = n + 1;
        return (ERR_BASE64_BUFFER_TOO_SMALL);
    }

    n = (slen / 3) * 3;

    for (i = 0, p = dst; i < n; i += 3)
    {
        C1 = *src++;
        C2 = *src++;
        C3 = *src++;

        *p++ = base64_enc_map[(C1 >> 2) & 0x3F];
        *p++ = base64_enc_map[(((C1 & 3) << 4) + (C2 >> 4)) & 0x3F];
        *p++ = base64_enc_map[(((C2 & 15) << 2) + (C3 >> 6)) & 0x3F];
        *p++ = base64_enc_map[C3 & 0x3F];
    }

    if (i < slen)
    {
        C1 = *src++;
        C2 = ((i + 1) < slen) ? *src++ : 0;

        *p++ = base64_enc_map[(C1 >> 2) & 0x3F];
        *p++ = base64_enc_map[(((C1 & 3) << 4) + (C2 >> 4)) & 0x3F];

        if ((i + 1) < slen)
            *p++ = base64_enc_map[((C2 & 15) << 2) & 0x3F];
        else
            *p++ = '=';

        *p++ = '=';
    }

    *dlen = p - dst;
    *p = 0;

    return (0);
}

/*
 * Decode a base64-formatted buffer
 */
int tiny_base64_decode(unsigned char *dst, int *dlen, unsigned char *src, int slen)
{
    int i, j, n;
    unsigned int x;
    unsigned char *p;

    for (i = j = n = 0; i < slen; i++)
    {
        if ((slen - i) >= 2 && src[i] == '\r' && src[i + 1] == '\n')
            continue;

        if (src[i] == '\n')
            continue;

        if (src[i] == '=' && ++j > 2)
            return (ERR_BASE64_INVALID_CHARACTER);

        if (src[i] > 127 || base64_dec_map[src[i]] == 127)
            return (ERR_BASE64_INVALID_CHARACTER);

        if (base64_dec_map[src[i]] < 64 && j != 0)
            return (ERR_BASE64_INVALID_CHARACTER);

        n++;
    }

    if (n == 0)
        return (0);

    n = ((n * 6) + 7) >> 3;

    if (*dlen < n)
    {
        *dlen = n;
        return (ERR_BASE64_BUFFER_TOO_SMALL);
    }

    for (j = 3, n = x = 0, p = dst; i > 0; i--, src++)
    {
        if (*src == '\r' || *src == '\n')
            continue;

        j -= (base64_dec_map[*src] == 64);
        x = (x << 6) | (base64_dec_map[*src] & 0x3F);

        if (++n == 4)
        {
            n = 0;
            if (j > 0)
                *p++ = (unsigned char)(x >> 16);
            if (j > 1)
                *p++ = (unsigned char)(x >> 8);
            if (j > 2)
                *p++ = (unsigned char)(x);
        }
    }

    *dlen = p - dst;

    return (0);
}

/**
 * @brief  Base64 解码
 *
 * @param  dst 输出字符串
 * @param  dst_len 输出字符串长度
 * @param  src 输入字符串
 * @param  src_len 输入字符串长度
 * @return 成功返回0，否则返回非0
 * @note   输出字符串需使用 rt_free 释放
 */
int string_base64_decode(char **dst, int *dst_len, const char *src, int src_len)
{
    *dst_len = (src_len * 6 + 7) >> 3;
    *dst = rt_malloc(*dst_len + 1);
    if (RT_NULL == *dst)
    {
        TRACE_E("%s, %d malloc failed", __FUNCTION__, __LINE__);
        return -1;
    }
    if (tiny_base64_decode((unsigned char *)*dst, dst_len, (unsigned char *)src, src_len))
    {
        TRACE_E("%s, %d base64_decode failed", __FUNCTION__, __LINE__);
        dst_len = 0;
        return -2;
    }
    else
    {
        (*dst)[*dst_len] = '\0';
    }
    return 0;
}

#endif
